1. Field of the Invention
The present invention relates to a device for processing fuel vapor. More particularly, it relates to a device which collects and traps fuel vapor emitted from, for example, a fuel tank of an internal combustion engine, and discharges the fuel vapor to the fuel tank or a carburetor inlet pipe.
2. Description of the Related Art
Fuel vapor accumulated in, for example, a fuel tank, should not be directly discharged to the atmosphere, since this results not only in atmospheric pollution but also in an increase in fuel consumption. In an attempt to eliminate this problem, Japanese Examined Patent Publication (Kokoku) No. 55-45748 discloses a construction for collecting fuel vapor wherein a canister housing containing, for example, charcoal as an absorbent, is provided between a fuel tank and an intake passage of a carburetor. However, in this construction wherein the canister is simply connected to the fuel tank, if the automobile body is severely jolted, liquid fuel in the fuel tank will impinge on a check valve provided in an inlet portion of the canister, and as a result, plasticizer in a flexible hose connected between the fuel tank and the inlet portion of the canister is dissolved into the liquid fuel flowing in the hose, and this plasticizer may impinge on and adhere to the check valve. If the plasticizer adheres to the check valve, the valve seat becomes sticky and the valve becomes hard to open, lowering the efficiency of the operation of the valve.